The purpose of the Immuno-Epidemiology Research Laboratory Core (Core C) is to provide a technical, intellectual and physical resource for the investigators in this Program Project Grant application. This laboratory has substantial experience performing all of the tasks and assays that are proposed for this Core in the present proposal and has been providing these services for the WHEALS project since its inception. As the central processing laboratory, Projects 1, 2, 3 and 4 will rely on Core C to process, track, store and/or ship archived and newly acquired blood, stool and dust specimens. Additionally, for Project 2, Core C will perform the isolation, culture and stimulation of peripheral blood mononuclear cells (PBMCs); dendritic cell and regulatory T cell phenotyping by multicolor flow cytometry; RNA analysis by realfime PCR; and Bio-Plex assay of secreted cytokines following stimulation of cultured PBMCs. The Specific Aims of Core C are: 1) To serve as the central collection, storage and processing laboratory for blood and dust samples collected in Projects 1, 2, 3 and 4; to ship plasma and dust samples to the dust and IgE Analysis Core (Core E) for Projects 2, 3, and 4; to ship stool samples to the Microbial Community Analysis Core (Core D) for Projects 1, 2 and 4; and, to ship processed dust samples collected in Project 2 to Dr. Lukacs' lab for use in Project 3, 2) To perform validated flow cytometric assays for phenotyping of dendritic cells and Tregs, and to perform validated Bio-Plex assays of secreted cytokines in stimulated PBMC culture supernatants for Project 2, in an efficient, reliable and consistent fashion, 3) To sen/e as a biorepository for plasma, DNA, RNA, dust, stool and other biological samples for use in future studies, 4) To provide data obtained from flow cytometry and Bio-Plex analyses to the Biostatistics and Data Management Core (Core B) for integration with data from Cores D and E and other data sources for statistical analyses for manuscripts and additional grant applications, and 5) To collaborate with the other investigators in the interpretation and integration of immunologic assay results into publications.